1. Field of the Invention
The present invention relates to a portable electrostatic liquid sprayer which is capable of being used while being carried by a person.
2. Description of the Related Art
A typical liquid sprayer uses an air compressor to blow air at a relatively high velocity through a sprayer head which extracts and atomizes liquid from a nozzle located in the sprayer head and deposits the atomized liquid onto crops or plants. An electrostatic sprayer electrostatically charges the atomized particles or droplets before they are expelled from the sprayer head to thereby improve the deposition of the droplets. The sprayer head and nozzle are typically made of a non-conducting material and are maintained at electrical ground. A high voltage is applied to a conductive electrode positioned near the outlet of the sprayer head to establish an electrostatic field capable of inductively charging the droplets issuing from the nozzle. Examples of electrostatic sprayers, which are known and are in use at the present time, are shown in U.S. Pat. Nos. 4,396,157 and 4,673,132 to Inculet et al.
Most electrostatic sprayers in use at the present time are relatively large and cumbersome since they require relatively large air compressors and liquid reservoirs for supplying the liquid to one or more nozzles in a large sprayer head or shroud. These relatively large and heavy sprayers are usually mounted on a tractor, truck, or other type of motorized vehicle or on a trailer pulled by the motorized vehicle. A high voltage source is required to supply a large enough voltage to the sprayer head electrode to induce the desired charge on the liquid particles. The high voltage source typically comprises a large and bulky battery coupled to a power pack for converting the low battery voltage to the necessary high voltage. The size and weight of the battery, liquid reservoir, compressor and other elements of existing electrostatic sprayers have been secondary considerations since these sprayers were intended to be carried by suitable tractors or other motorized vehicles.
It is desirable, however, to provide a portable electrostatic sprayer which is capable of being used while being carried by a person. The electrostatic sprayers currently being used are unsuitable for this purpose for a plurality of reasons. First, the existing sprayers are much too large and heavy. Second, the sprayer heads typically have limited movement making them undesirable for manipulation by a single person to spray in variable directions. Third, even if some of the required elements are reduced in size to create a smaller sprayer, a high voltage source is still necessary and must be provided and carried along with the unit. It is not practical for a single person to carry the battery and power pack typically used on existing electrostatic sprayers.
Portable engine back-packs for blowers and sprayers are known, but so far as is known, no one has previously solved the problems of a portable back-pack type unit for electrostatic sprayers.